fix: dump unreferenced circular objects on request

extension/meminfo.c

@@ -16,9 +16,13 @@
 #include "SAPI.h"
 #include "zend_API.h"
 
+#define MEMINFO_DUMP_PARAMETERS "r|b"
+#define MEMINFO_OBJECT_STORE_FIRST_VALID_INDEX 1
+
 #if PHP_VERSION_ID >= 80000
 ZEND_BEGIN_ARG_INFO_EX(arginfo_meminfo_dump, 0, 0, 1)
     ZEND_ARG_INFO(0, output_stream)
+    ZEND_ARG_INFO(0, include_unreferenced)
 ZEND_END_ARG_INFO()
 
 const zend_function_entry meminfo_functions[] = {
@@ -53,13 +57,14 @@ zend_module_entry meminfo_module_entry = {
 PHP_FUNCTION(meminfo_dump)
 {
     zval *zval_stream;
+    zend_bool include_unreferenced = 0;
 
     int first_element = 1;
 
     php_stream *stream;
     HashTable visited_items;
 
-    if (zend_parse_parameters(ZEND_NUM_ARGS(), "r", &zval_stream) == FAILURE) {
+    if (zend_parse_parameters(ZEND_NUM_ARGS(), MEMINFO_DUMP_PARAMETERS, &zval_stream, &include_unreferenced) == FAILURE) {
         return;
     }
 
@@ -78,6 +83,9 @@ PHP_FUNCTION(meminfo_dump)
     php_stream_printf(stream, "  \"items\": {\n");
     meminfo_browse_exec_frames(stream, &visited_items, &first_element);
     meminfo_browse_class_static_members(stream, &visited_items, &first_element);
+    if (include_unreferenced) {
+        meminfo_browse_object_store(stream, &visited_items, &first_element);
+    }
 
     php_stream_printf(stream, "\n    }\n");
     php_stream_printf(stream, "}\n}\n");
@@ -186,6 +194,24 @@ void meminfo_browse_class_static_members(php_stream *stream,  HashTable *visited
     }
 }
 
+void meminfo_browse_object_store(php_stream *stream, HashTable *visited_items, int *first_element)
+{
+    zend_objects_store *object_store = &EG(objects_store);
+    uint32_t object_index;
+
+    for (object_index = object_store->top; object_index-- > MEMINFO_OBJECT_STORE_FIRST_VALID_INDEX;) {
+        zend_object *object = object_store->object_buckets[object_index];
+        zval object_zval;
+
+        if (!IS_OBJ_VALID(object)) {
+            continue;
+        }
+
+        ZVAL_OBJ(&object_zval, object);
+        meminfo_zval_dump(stream, NULL, NULL, &object_zval, visited_items, first_element);
+    }
+}
+
 void meminfo_browse_zvals_from_symbol_table(php_stream *stream, char* frame_label, HashTable *p_symbol_table, HashTable * visited_items, int *first_element)
 {
     zval *zval_to_dump;

extension/php_meminfo.h

@@ -17,6 +17,7 @@ zend_ulong   meminfo_get_element_size(zval* z);
 // Functions to browse memory parts to record item
 void meminfo_browse_exec_frames(php_stream *stream,  HashTable *visited_items, int *first_element);
 void meminfo_browse_class_static_members(php_stream *stream,  HashTable *visited_items, int *first_element);
+void meminfo_browse_object_store(php_stream *stream, HashTable *visited_items, int *first_element);
 
 void meminfo_zval_dump(php_stream * stream, char * frame_label, zend_string * symbol_name, zval * zv, HashTable *visited_items, int *first_element);
 void meminfo_hash_dump(php_stream *stream, HashTable *ht, zend_bool is_object, HashTable *visited_items, int *first_element);

extension/tests/bug-github-83_unreferenced_cycle.phpt

@@ -0,0 +1,34 @@
+--TEST--
+Check that unreferenced circular object references are dumped
+--SKIPIF--
+<?php if (!extension_loaded('meminfo')) print 'skip'; ?>
+--FILE--
+<?php
+class CycleNode
+{
+    public $peer;
+}
+
+$first = new CycleNode();
+$second = new CycleNode();
+$first->peer = $second;
+$second->peer = $first;
+unset($first, $second);
+
+$dump = fopen('php://memory', 'rw');
+meminfo_dump($dump, true);
+rewind($dump);
+$meminfoData = json_decode(stream_get_contents($dump), true);
+fclose($dump);
+
+$cycleNodeCount = 0;
+foreach ($meminfoData['items'] as $item) {
+    if (isset($item['class']) && $item['class'] === 'CycleNode') {
+        $cycleNodeCount++;
+    }
+}
+
+echo "Unreferenced cycle objects found: ".$cycleNodeCount."\n";
+?>
+--EXPECT--
+Unreferenced cycle objects found: 2